Reinforced E30 subframe

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Jeroen
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Reinforced E30 subframe

Post by Jeroen »

The 320iS uses the same subframe as any stock E30. There are already known problems with the subframe not coping with the 325i enige on top, let alone with the 320iS's more powerful and definitely more vibrating engine.

For the car of a friend of mine this has led to the engine mounts (which are 'ears' welded to the subframe, not the strongest construction) slowly being torn off the subframe... noticeable through rust at the seams.

So... we decided to go for a used subframe and modify it:

sandblasted subframe

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Then.. fitted a Turner Motorsport subframe reinforcement kit:

inner reinforcement plate

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inside of the ear welded as well, on top of the original welding seams on the outside

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outer reinforcement plate

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and zinc covering the whole subframe now

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Now it's time to add some primer (if necessary?!) and paint the subframe black again.

Please note that any E30 subframe will suffer from this if the car is equipped with a strong engine an/or used in a thorough :P way. I'll start a search to build my own now...

Last but not least... this is my buddy and almost neighbour Folkert who took care of the sandblasting and the welding... what kinda chassis needs that much welding... it's a french car! :twisted: He drives a 325iX himself though... in the process of being track prepped. BTW he's also the guy that did the welding on the cage fittings for my track car.

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Many thanks Folkert!


Regards/groeten, Jeroen

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Hannes

Post by Hannes »

Well, it is a comforting thought that that this very subframe will be under my car soon. No half measures there! Very nice work!

Many thanks to Folkert also, for (indirectly) helping me out! And Jeroen, it is now official: I must be your only friend who is all fingers and thumbs, then...

Again, many thanks!

Hannes
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Jeroen
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Post by Jeroen »

What can I say... still waiting for several parts for your car, but in the meantime you know how to keep me busy... and Folkert as well :P
Regards/groeten, Jeroen

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Madhatter
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Post by Madhatter »

The first plate wont do a whole lot as far as support goes depending on where the mount actually tears from. The last plate over the top and welded to the subframe is the one which will give added strength to stop the whole thing coming away from the subframe.

Im guessing you have a problem with the bolts tearing out of the metal itself, its usually movement which causes this, once the motor has leverage to move about it will tear through metal pretty easily.

Nice work all the same.
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Jeroen
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Post by Jeroen »

Thanks. The inner plate prevents the engine bushing from ripping out of the metal. But that was not the case here: as in most cases the welding seams of the ears were torn, that's where the stress rips the ears off the subframe.
Regards/groeten, Jeroen

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Madhatter
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Post by Madhatter »

holy crap, something got struck by lightning and we just lost power :shock:

Yeah, that outer plate is the one which will give you support to help stop it tearing away from the subframe, it should help displace the load across both joints to help limit it.

Looks like an easy mod someone can do at home with a stick welder, some metal and a can of paint. :)
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Jeroen
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Post by Jeroen »

Yep, definitely is an easy mod. I'll prepare one for my car now as well...
Regards/groeten, Jeroen

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Kogando
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Re: Reinforced E30 subframe

Post by Kogando »

Well done! :)
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325ixbaur
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Re: Reinforced E30 subframe

Post by 325ixbaur »

Even my 318i has a torn subframe...that's why I was looking for this topic :)

Gr Jeroen
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Jeroen
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Re: Reinforced E30 subframe

Post by Jeroen »

Well the topic is still up here! I've seen those fail several times already, mostly with 325i's and M3's but that doesn't say too much as that's by far the majority of the E30's I've serviced. But of course this could happen to any type. My 320iS had one that was still intact but as I had to remove it to give the car fresh con rod bearings I decided to replace it by a reinforced and freshly powder coated example. When in Rome...

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Regards/groeten, Jeroen

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325ixbaur
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Re: Reinforced E30 subframe

Post by 325ixbaur »

As I want (have) to replace my wheel bearings, I want to "renew" the complete front. And it's quite easy, as I have a complete front in my shed. This means that I can prepare that one, while still driving my 318i.
-Subframe
-Lowered springs
-Aircooled brakes from a 320i
-Bushes
-Tie rods

And why not better my welding skills... ;)

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Jeroen
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Re: Reinforced E30 subframe

Post by Jeroen »

Good plans! I'd go for the solid trailing arm bushes as well then.
Regards/groeten, Jeroen

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Re: Reinforced E30 subframe

Post by garagistic »

For those who cant weld, we have tons of cores in our subframe core exchange program here:
https://store.garagistic.com/E30-reinfo ... 20subframe

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